Seems like your money is stuck due to a force closure, not because your tx pays a low fee.

Your wallet and your counterparty's wallet couldn't agree on what fee to pay to close the channel. Your wallet thought fees were pretty high so you wanted to pay a high fee to get your transaction confirmed; their wallet thought fees were pretty low and they didn't want to pay a high fee and potentially collect less money than they think is due to them.

When your wallet can't come to consensus with its counterparty, it ignores them and withdraws your money using its presigned force closure transaction. But that also means "one of you might be misbehaving," so the force closure transactions are timelocked to give your counterparty time to prove whether you've done anything malicious. You haven't, so you'll be fine, but you do have to wait while an up-to-2-week timer runs out.

This is an inherent difficulty with lightning: you can't do "whatever you want" with your lightning utxos because they are "shared" utxos. Your counterparty has half of the keys, so anything you want to do with them, they have to agree on it. In this case, you couldn't agree on what to do with that utxo "right now," so you have to use whatever you last agreed on -- and lightning always ensures the "last" thing you agreed on is a unilateral withdrawal transaction (so you'll definitely get your money out), but it's timelocked.